I have a question about setting the Population size value when creating a Study.

The Autodesk help page says “A rule of thumb is to set the population size to at least three times the number of inputs.”

However, when I actually try to set it, the Study screen in Generative Design says as an issue that “Population Size must be equal or greater than 4 and a multiple of 4.”

I would like to know how to determine the value of Population size.

This is a good guideline, though in some cases you may want a multiple is ten or two or some unrelated number. It’s a rule of thumb not a steadfast certainty after all.

So as the value has to be divisible by four, round up to the next multiple of four. I.E if you have 3 inputs, multiply that by 3 to get 9, the next multiple of four is 12, so use 12 to start with. That said generally I don’t recommend dropping below 20 - again these are guidelines, and you need to learn what works for the type of problems you are solving.

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Thanks for your reply.

Thanks to you I understand that being a multiple of 4 should be the highest priority.

However, I do not understand why it is a multiple of 4.

Is it because when using NSGA-II, you need two families to breed?

Yes. Four is a requirement of the implementation of the nsga2 algorithm.

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